The holder of a Syrian passport found near the body of one of the gunmen who died in Friday night’s attacks in Paris passed though Greece in October, a Greek minister told Reuters.

“The holder of the passport passed through the island of Leros on 3 October 2015, where he was identified according to EU rules,” said Nikos Toscas, Greece’s deputy minister in charge of policing.

A Greek police source told Reuters that European countries had been asked to check the passport holder to see if they had been registered.

While this heavily implies that one of the gunman came into Europe along with refugees, Syrian passports are known to be valuable currency amongst those trying to enter Europe, and it is not yet confirmed whether the holder of the passport is indeed the perpetrator.